Food product and method and apparatus for baking

ABSTRACT

Provide an oven and optional cooking accessories having a high emissivity thermal protective layer on a substrate surface which comprises a metal or ceramic. The layer comprises from about 5% to 30% of an inorganic adhesive, from about 45% to 92% of at least one filler, and from about 1% to 25% of one or more emissivity agents; or from about 5% to 35% of colloidal silica, colloidal alumina, or combinations thereof, from about 23% to 79% of at least one filler, and from about 1% to 25% of one or more emissivity agents.

BACKGROUND OF THE INVENTION

Ovens, and food products prepared in ovens, have been known forthousands of years. Baking food products including bread has alsoexisted for thousands of years. Many different kinds of ovens forcooking and baking exist. Domestic ovens include conventional andconvection ovens, and smaller appliances such as toaster ovens, and thelike. Ovens for commercial use include those used in restaurants andthose used in widespread commercial food production. Ovens forrestaurants include revolving ovens, rack ovens, convection ovens,multiple deck ovens, pizza ovens, steam tube ovens, and the like. Ovensfor commercial food production include direct fired tunnel ovens, steelband ovens, steel plate ovens, pita ovens, direct fired tray ovens,indirect fired tunnel ovens, and impingement ovens, and the like. All ofthese ovens are well known in the art, and have many advantages fortheir particular consumer or commercial applications. Ovens are heateddirectly or indirectly. Heat sources can be gas, oil, electric or othercombustible materials. The heat in an oven may be generatedelectrically, or by using combustible fluids. The walls of commercialcooking ovens are typically metal but may be coated/layered withreflective or refractive materials, including nonstick layers andporcelain.

In all cases, satisfactory baker's ovens are difficult to produce. ‘Hotspots’ and ‘cold spots’ are created throughout the internal cookingregion of most ovens, whether consumer or commercial, resulting inuneven application of heat to the baked products and reduced production.Numerous efforts have been made to eliminate this problem in commercialapplications by providing rotary supports, belts, and rollers whichcontinually move cooking products relative to the heating elements.Furthermore, efforts have been made to eliminate the problem of unevenheating, coupled with the preheating troubles and oven cleaning, inconsumer ovens by varying the materials used in the walls of the ovens,and by the use of targeted temperature monitoring with controllersdesigned to actively adjust the thermal properties within the oven.Similar active controllers may be used in commercial applications aswell. Nevertheless, the problems of uneven heat within the cookingregion of traditional ovens, both commercial and consumer, remain.Inevitably some of the baked products produced in most ovens areunevenly cooked, and in commercial applications, this can result inunevenly cooked products and/or product loss from under or over cooking.

Ovens providing consistent heat throughout the internal cooking regionor zones are desirable. It is desirable to provide a uniformly heatedcooking region to minimize the amount of prepared food product that mustbe discarded. Numerous efforts have been used in the past to attempt toaddress this issue.

The effect of the emissivity of surfaces within ovens have been known toeffect the cooking process. U.S. Patent Application No. 2010/006,559teaches a consumer oven having an element with different coatings on theelement having varying emissivity characteristics, optionally includinga ceramic coating, designed to facilitate baking on one side, andbroiling on the other.

The use of cooking pans, especially involving microwave cookingcontainers, having desirable emissivity characteristics are known in theprior art. Typically such inventions have involved simple dark paint,surface carbonizing, porcelain, or ceramic surfaces. As an example, U.S.Pat. No. 3,078,006 issued on Feb. 19, 1963 discloses a silicone resincoated metallic bake form having nonstick properties and improvedradiant heat absorption characteristics in which small amounts of carbonare incorporated into the silicone resin coating. In spite of business'efforts, a sheet of cookies baked in present ovens regardless of the panused usually result in some cookies being more cooked then othersdepending on their position within the cooking region.

Efforts to control the thermal environment within an oven during baking,and pans having desired thermal characteristics, are known. It is alsoknown to provide ovens that operate, in part, by having cooking zones.The walls of some ovens have been coated in ceramic, porcelain,aluminum, dark paint, and the like in an effort to produce a desirabletemperature within the cooking region or to facilitate cleaning of thesides of the oven. Other ovens simply have exposed metal surfaces.

Similarly, cooking pans have been modified to produce desirable thermalcharacteristics and to facilitate cleaning of the cooking surface of thepan. Simple metal racks, metal rollers, and metal conveyor belts aretypically used in commercial ovens equipped with either racks, rollers,belts, or the like.

U.S. Pat. No. 6,818,869 issued on Nov. 16, 2004 teaches a multiplepanel, or deck, oven having individual controls for combine conductiveand radiant heating panels, and providing the option of having 1-5different cooking zones between various panels.

U.S. Pat. No. 6,229,117 issued on May 8, 2001 teaches a bread refreshingoven having an interior lining of the oven is rebounded fused silicafoam, and a tray made of fused silica in the form of a non-porousceramic is used with the oven.

U.S. Pat. No. 4,164,643, issued on Aug. 14, 1979, teaches anenergy-efficient bi-radiant oven system in which a black coated aluminumpan is disclosed with an emissivity of E=0.79; however, the oven used inthis system has an oven lining with a highly reflective metal and anemissivity value on the order of E=0.05.

Energy efficient ovens with even heat distribution remain desirable.Food loss due to uneven and unpredictable oven performance remains aproblem. It is desirable to have an oven which will heat evenly within acooking zone to reliably and consistently produce the same cooked foodproducts for mass distribution.

SUMMARY OF THE INVENTION

The present design relates to food products and a method and apparatusesfor cooking and especially baking food products. Specifically, thepresent design relates to a method or process of cooking food productsin an oven having a high emissivity thermal protective layer disposed onmetallic and ceramic internal surfaces thereof, ovens having a highemissivity thermal protective layer disposed on the metallic internalsurfaces thereof, and food products produced thereby.

An oven according to the present design has a housing including aceiling, floor, two opposite side walls and an opening therethroughforming at least one internal heating zone. A conventional heating meansis provided to heat the zone, and may include gas or oil burners,electric resistance coils, steam tubes, and the like. At least onesubstrate surface is provided, within the oven adjacent the heatingzone, including the ceiling, floor, walls, heating means, panel, door,and the like, have a high emissivity thermal protective layer disposedthereon.

The high emissivity thermal protective layer for metal surfaces has fromabout 5% to about 30% of an inorganic adhesive, from about 45% to about92% of at least one filler, and from about 1% to about 25% of one ormore emissivity agents. The high emissivity thermal protective layer forceramic surfaces has from about 5% to about 35% of colloidal silica,colloidal alumina, or combinations thereof, from about 23% to about 79%of a filler, and from about 1% to about 25% of one or more emissivityagents.

Oven cooking accessories used in the process for making the cookedproduct according to the present design, and include pans, cookingsheets, racks, and the like. The cooking accessories have a cookingsurface for coming into contact with food and an outside surfaceopposite the cooking surface having a high emissivity thermal protectivelayer disposed on the outside surface thereof. Alternative embodimentspermit the high emissivity thermal protective layer to be disposed onthe entire external surface thereof, including both the outside and thecooking surfaces. A nonstick layer, or other layer, as is well known inthe art may be disposed on the cooking surface. The thermal protectivelayer may be disposed between the cooking surface and the nonsticklayer, or other layer.

A process of making a food product, and the food products made therein,are encompassed by the present design. The process for making the foodproduct takes less time and requires less energy than the conventionalprocess without the high emissivity thermal layer disposed on substratesurfaces within the oven. Food products made in the oven of the presentdesign and by the process of the present design are more uniform both interms of subsequent batches and in terms of food product in differentparts of the oven.

An aspect of the present design is ovens having at least one uniformheating region, or zone, for evenly cooking a food product therein.Alternative embodiments of the present design may provide for multipleheating zones. Examples of commercial ovens having heating multiplezones include tunnel ovens which are either directly or indirectly firedbut provide for multiple zones through which the food product travels.Another example may be provided with some rack, deck, tray, revolving,or pizza ovens which may provide separate heating zones as shelvesincluding directly heating each shelf.

Another aspect of the present design is to provide a prepared foodproduct cooked in an oven containing a high emissivity coating accordingto the present design disposed on the internal metallic surfaces thereofto provide consistently even heat throughout each heating region andzone thereof. The resultant food products produced by the present designare more uniform in size, shape, and extent cooked. Multiple batches arealso more uniform. Ovens according to the present design provide asignificantly more uniform cooking environment than other ovens lackingthe thermal protective layer disposed thereon resulting in substantiallyuniform baked products.

Yet another aspect of the present design is to provide a cooking panhaving a high emissivity thermal protective layer according to thepresent design disposed on the outside of an otherwise conventionalcooking pan. Food products prepared in such pans are significantly moreuniform in their size, shape, and extent cooked then food productsprepared in conventional pans. The high emissivity thermal protectivelayer functions to even out the temperature and thermal heat signatureincreasing the uniformity of the heat within the ovens of the presentdesign.

A further aspect of the present design is to provide a food productwhich is uniform in size and shape because of the uniform thermalenvironment within the oven. Food products prepared in such pans andovens are substantially uniform in their size, shape, and extent cookedthen food products prepared in conventional ovens and pans. The presentdesign improves the wavelength distribution in the infraredcooking/baking wavelengths.

An aspect of the present design is to provide a high emissivity thermalprotective layer disposed on the internal surfaces of an oven to producea cooking environment in which the food product cooked or baked withinthe oven is uniformly heated at the optimum temperature. The emissivitylayer results in the reduction of baking time yielding in increasedbaking capacity and/or the reduction of energy need to bake grain baseproducts.

Yet another aspect of the present design is to provide a method of andapparatus for baking food products, and food products baked thereby, inwhich substantially all of the food products prepared from the samevolume of a recipe are uniform in size and shape, and that areconsistent through different runs over extended periods of time. It isessential for mass food production to be essentially uniform. Thepresent design furthers this goal.

These and other aspects of the present design will become readilyapparent upon further review of the following drawings andspecification.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the described embodiments are specifically setforth in the appended claims; however, embodiments relating to thestructure and process of making the present design, may best beunderstood with reference to the following description and accompanyingdrawings.

FIG. 1 is a breakaway environmental view of a direct fired tunnel ovenshowing the inside of the tunnel oven, and oven accessories, having ahigh emissivity thermal protective layer disposed thereon according toan alternative embodiment of the present design.

FIG. 2A is a diagrammatic view of a direct fired tunnel oven using aconveyor belt system and having a high emissivity thermal protectivelayer disposed thereon according to alternative embodiments of thepresent design.

FIG. 2B is a diagrammatic view of an indirect fired tunnel oven using aconveyor belt system according to an alternative embodiment of thepresent design having high emissivity thermal protective layer therein.

FIG. 3 is a diagrammatic view of a rack oven according to yet anotheralternative embodiment of the present design having a high emissivitythermal protective layer therein.

FIG. 4 is a diagrammatic view of a convection oven with a highemissivity thermal protective layer therein according to an alternativeembodiment of the present design.

FIG. 5 is a diagrammatic view of a direct fired tray oven with a highemissivity thermal protective layer therein according to an alternativeembodiment of the present design.

FIG. 6 is a perspective view of a revolving oven according to analternative embodiment of the present design having a high emissivitythermal protective layer therein.

FIG. 7 is a diagrammatic view of an impingement oven with a highemissivity thermal protective layer therein according to an alternativeembodiment of the present design.

FIG. 8 is a diagrammatic view of a multiple deck oven according to anembodiment of the present design with a high emissivity thermalprotective layer therein.

FIG. 9 is an environmental side view of a conventional consumer ovenaccording to an embodiment thereof with a high emissivity thermalprotective layer therein.

FIG. 10 is a diagrammatic view of a consumer toaster oven with a highemissivity thermal protective layer therein according to an alternativeview of the present design.

FIG. 11A is a side view of a burner shield according to an alternativeembodiment of the present design with a high emissivity thermalprotective layer thereon.

FIG. 11B is a top view of a burner shield according to an embodiment ofthe present design with a high emissivity thermal protective layerthereon.

FIG. 11C is a side view of a burner shield and burner assembly accordingto the present design with a high emissivity thermal protective layerthereon.

FIG. 12 is a side cutaway view of a cake pan according to an alternativeembodiment of the present design with a high emissivity thermalprotective layer.

FIG. 13 is a partial side cutaway view of a cookie sheet according to analternative embodiment of the present design with a high emissivitythermal protective layer.

FIG. 14 is an elevated environmental view of a loaf pan according to anembodiment of the present design with a high emissivity thermalprotective layer.

FIG. 15 is a cutaway view of a rack according to the present designshowing the high emissivity thermal protective layer disposed on theouter surface thereof.

FIG. 16 is a side view of a cooking accessory having a high emissivitythermal protective coating disposed on the cooking surface and on theoutside surface.

FIG. 17 is a side view of a cooking accessory according to the presentdesign having a high emissivity thermal protective layer disposedbetween the cooking surface and a nonstick surface layer.

FIG. 18 is an environmental view of a panel according to an alternativedesign.

FIG. 19 is an environmental view of an insert according to yet anotheralternative design.

Similar reference characters denote corresponding features consistentlythroughout the attached drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

An oven 12 according to the present design, as shown in FIGS. 1-10, hasa housing 14 including a ceiling 16, floor 20, two opposite side walls15 and 17, and an opening 21 therethrough forming at least one internalheating zone 34. A conventional heating means 38 may includeconventional gas burners, coils, steam tubes, and the like, whichheating means 38 may have a high emissivity thermal protective layer 18disposed thereon. At least one substrate surface is provided includingthe ceiling 16, floor 20, walls 15 and 17, heating means 38, panel 40,door 42, and the like, have a high emissivity thermal protective layer18 disposed thereon. The panel 40 may be placed in the oven to protectthe walls 15 and 17, the back wall 23, the ceiling 16, or the floor 20,and may be either ceramic or metal. The heating means 38 may be a directfired burner, an indirect fired burner, or direct or indirect heatingelectric elements. FIGS. 18 and 19 show cooking accessories that may beused in conventional ovens, and include a panel 40 which may be usedalone or if more than one panel 40. Another alternative is shown thathas an insert 140 with a high emissivity thermal protective layer 18thereon either the inside or outside surfaces thereof according to yetanother alternative design with a heat zone 34 encompassed therein.

The high emissivity thermal protective layer 18 for metal surfaces hasfrom about 5% to about 30% of an inorganic adhesive, from about 45% toabout 92% of at least one filler, and from about 1% to about 25% of oneor more emissivity agents. The high emissivity thermal protective layer18 for ceramic surfaces has from about 5% to about 35% of colloidalsilica, colloidal alumina, or combinations thereof, from about 23% toabout 79% of at least one filler, and from about 1% to about 25% of oneor more emissivity agents.

The present design encompasses any cooking oven having a high emissivitythermal protective layer 18 according to alternative embodiments of thepresent design. FIG. 1 shows a direct fired tunnel oven which is a typeof oven 12 that has multiple heating zones 34; and a conveyor system 22,24, and 26. The conveyor system 22, 24, and 26 comprises rollers 22 orbelts 24 to move racks 28 containing cooking pans 30 therein througheach hating zone 34. A high emissivity thermal protective layer may bedisposed at least partially on the conveyor system 22, 24, and 26,rollers 22, belts 24, or racks 28, or combinations thereof.

FIG. 2A shows direct fired tunnel oven 12 using a conveyor belt system22, 24, and 26, and having a high emissivity thermal protective layer 18disposed therein. FIG. 2B shows an indirect fired tunnel oven 12 using aconveyor belt system 22, 24, and 26, similar to the direct fired tunneloven 12, with a high emissivity thermal protective layer 18 disposedtherein. Indirect and direct fired tunnel ovens 12 can have multipleheating zones 34 to facilitate cooking the food product in the mostoptimum fashion. Each heating zone 34 may have a different temperatureas appropriate. FIG. 3 shows a rack oven which may have separate heatingzones 34 between each rack which may have a high emissivity thermalprotective layer 18 disposed on the rack as well as the walls, ceiling,and floor. FIG. 4 shows a convection oven with a high emissivity thermalprotective layer 18 disposed therein, and also on the door 42. FIG. 5shows a direct fired tray oven which may have multiple heating zones 34therein in the same manner as a tunnel oven. Indirect fired tray ovensare also known. FIG. 6 shows a revolving oven which has doors 42 and arotating rack system 50 with a high emissivity thermal protective layer18. FIG. 7 shows an impingement oven that may also have multiple heatingzones 34 therein as well. FIG. 8 shows a multiple deck oven that mayhave a heating zone 34 within each deck. FIG. 9 shows a conventionalconsumer oven, and FIG. 10 shows a consumer toaster oven.

An alternative to a conventional burners and burner shields is shown inFIGS. 11A-11C. FIGS. 11A and 11B show a burner shield 16 which directsthe heat radiation as it is emitted from the burner 38. Either or boththe burner 38 and/or the burner shield 16 may have a high emissivitythermal protective layer 18 disposed thereon. Burner shields 16 with thehigh emissivity thermal protective layer 18 thereon function superior tothe same burner shield 16 without the layer 18 thereon. It is to beunderstood that the layer 18 may be disposed on either side of a surfaceand will depart the desired characteristics to the coated material.

Oven cooking accessories shown in FIGS. 12-17, including pans 30,cooking sheets 30, racks 28, and the like, have a cooking surface 42 forcoming into contact with food and an outside surface 44 opposite theinside surface 42 having a high emissivity thermal protective layer 18disposed on the outside surface 44 thereof. Alternative embodimentspermit the high emissivity thermal protective layer 18 disposed on theentire external surface 42 and 44 thereof including the outside surface44 and the cooking surface 42. A nonstick layer 46, as shown in FIG. 17,or other layer as is well known in the art may be disposed on thecooking surface 42. The thermal protective layer may be disposed betweenthe cooking surface 42 and the nonstick layer 46. The cookingaccessories may be composed of metals, fiber, or silicone rubber, andmay or may not have an emissivity shield disposed thereon, or disposedin layers thereof.

A process of making a food product and the food product made therein areencompassed by the present design. The process for making the foodproduct takes less time and requires less energy than the conventionalproduct without the high emissivity thermal layer disposed on substratesurfaces within the oven. Food products made in the oven of the presentdesign and by the process of the present design are more uniform both interms of subsequent batches and in terms of food product in differentparts of the oven.

Substrate surfaces include the oven walls, ceilings, floor, door, racks,radiant tubes, steam tubes, tube shields, reflectors, heating elements,burners, burner shields, panels, inserts, rollers, conveyor belts, ovenframes, and the like, including all exposed metallic surfaces within anoven. Substrate surfaces also include apparatuses used within the ovenbut removable from the oven including racks, cooking pans, bakingsheets, and any surface of carrier rack pans. Commercial ovensencompassed by the present design include, but are not limited to,direct and indirect heated tunnel ovens, multi deck ovens, steam tubeovens, impingement ovens, hybrid ovens, and consumer ovens. Consumerovens encompassed by the present design, include but are not limited toconventional ovens, whether gas fired or electric, convection ovens,toaster oven, bread machines, toasters, and the like. Multiple deckovens encompassed by the present design, whether electric or gas fired,conventional or convection, include pizza ovens, steam tube ovens, rack,rotating rack, deck ovens, modular ovens, and the like. Panels andinserts are metal or ceramic accessories that can be placed in an ovenin lieu of coating the oven with a high emissivity thermal protectivelayer. The Panels may be flat with two sides, inside and outside.Alternatively inserts which are cap-like with an opening within to forma heat zone may be used. An insert may have a ceiling and sides justlike the oven, with an opening therein forming the heat zone. The itemto be cooked is placed within the opening either through a side, or byhaving the insert placed on top of the food to be cooked.

Cooking accessories that come into direct contact with food may alsohave a high emissivity thermal protective layer 18 according to thepresent design disposed on the surfaces thereof, or integrated withinthe multiple layers. It is most desirable to have a high emissivitylayer disposed on the bottom surfaces of pans, sheets, and racks. Analternative also permits the high emissivity layer to be disposed onboth, top and bottom, sides. In some alternative embodiments of thepresent design, ovens and cooking accessories may have nonstick layers,or other layered configurations, with the high emissivity layer disposedeither under or on top of the nonstick layer. Alternatively, panelshaving a high emissivity layer disposed thereon may be placed within theoven. Alternatively, the oven may have a hearth that the cooked productsits directly on including wire mesh belts, steel plate, hinge plate,stone plates, ceramic plates, and manmade composite cement plates.

Metal and alloy substrate surfaces are found in most ovens, and includemost surfaces including walls, ceilings, floors, doors, racks, steamtubes, tube shields, ducts, heat exchangers, catalytic plates,reflectors, burners, burner shields, panels, rollers, conveyors belts,and the like. Ceramic materials may be used in ovens for heatingelements, shields, reflectors, radiant tubes, team tubes, and the like,and may also be used in oven walls, ceilings, floors, and the like, andparts thereof.

The ovens covered by the present design may be fueled by gas (includingnatural, propane, LPG, butane, and city gas), oil (including No. 2 fueloil, bunker fuel, diesel, coal oil, and naphtha), coal, wood, biomass,fuel cell, ethanol, and electricity.

Food products include bread, buns, rolls, bagels, cakes, and the like.Breads include white breads, whole grain breads, specialty breads,highly fermented breads, hearth breads, and pan breads. Specialty breadsinclude chaibatta breads, pita bread, and flat bread. Buns include whitebuns, whole grain buns, specialty buns, highly fermented buns, hearthbuns, and pan buns. Rolls include specialty rolls, whole grain rolls,Kaiser rolls, split top rolls, cross rolls, water rolls, bulky rolls,sub rolls, grinder rolls, torpedo rolls, and the like, both pan andhearth baked. Bagels, bialys, and bagel twists are included, as well.Sweets include cakes, pies, pastries, cookies, crackers, and sweetgoods. All grain based products including gluten and gluten freeproducts are included.

The thermal protective layer 18 for metallic substrates comprises fromabout 5% to about 30% of an inorganic adhesive, from about 45% to about92% of at least one filler, and from about 1% to about 25% of one ormore emissivity agents; or for ceramic substrates comprises from about5% to about 35% of colloidal silica, colloidal alumina, or combinationsthereof, from about 23% to about 79% of a filler, and from about 1% toabout 25% of one or more emissivity agents.

The high emissivity thermal protective layer 18 may be applied as a highemissivity multifunctional thermal protective coating. Alternativesuitable coatings and methods of application are described in U.S. Pat.Nos. 7,105,047 and 6,921,431, the contents of which are incorporatedherein in their entirety.

A high emissivity coating suitable for forming a thermal protectivelayer on a metal/alloy substrate surface of the present design maycontain from about 5% to about 30% of an inorganic adhesive, from about45% to about 92% of at least one filler, and from about 1% to about 25%of one or more emissivity agents, in a dry admixture. Preferably, thedry admixture also contains from about 1% to about 5% of a stabilizer.

An alternative high emissivity coating suitable for forming a thermalprotective layer on a ceramic surface within a cooking oven according toalternative embodiments of the present design may contain from about 5%to about 35% of colloidal silica, from about 23% to about 79% of atleast one filler, from about 1% to about 25% of one or more emissivityagents. Preferably, a thermal protective layer of the present designalso contains from about 1.5% to about 5.0% of a stabilizer.

As used herein, all percentages (%) are percent weight-to-weight, alsoexpressed as weight/weight %, % (w/w), w/w, w/w % or simply %, unlessotherwise indicated. Also, as used herein, the terms “wet admixture”refers to relative percentages of the composition of the thermalprotective coating in solution and “dry admixture” refers to therelative percentages of the composition of the dry thermal protectivecoating mixture prior to the addition of water. In other words, the dryadmixture percentages are those present without taking water intoaccount. Wet admixture refers to the admixture in solution (with water).“Wet weight percentage” is the weight in a wet admixture, and “dryweight percentage” is the weight in a dry admixture without regard tothe wet weight percentages. The term “total solids”, as used herein,refers to the total sum of the silica/alumina and the alkali or ammonia(NH₃), plus the fraction of all solids including impurities. Weight ofthe solid component divided by the total mass of the entire solution,times one hundred, yields the percentage of “total solids”.

Method of preparation of coating involves applying a wet admixture ofthe coating to the surface to be coated. Alternative methods may includespraying the wet admixture on the surface or atomizing the dry admixtureand coating the surface accordingly.

In a coating solution according to the present design, a wet admixtureof the thermal protective coating, to be applied to metal/alloysubstrate surfaces within a cooking oven, contains from about 6% toabout 40% of an inorganic adhesive, from about 23% to about 46% of afiller, from about 0.5% to about 10% of one or more emissivity agents,and from about 18% to about 50% water. In order to extend the shelf lifeof the coating solution, from about 0.5% to about 2.5% of a stabilizeris preferably added to the wet admixture. The wet admixture coatingsolution contains between about 40% and about 60% total solids.

In a coating solution according to the present design, a wet admixtureof an alternative thermal protective coating, to be applied to ceramicsubstrate surfaces, contains from about 15% to about 45% of colloidalsilica, from about 23% to about 55% of at least one filler, from about0.5% to about 15% of one or more emissivity agents, from about 0.5% toabout 2.5% of a stabilizer and from about 18% to about 40% water. Thewet admixture coating solution contains between about 40% and about 70%total solids.

The inorganic adhesive is preferably an alkali/alkaline earth metalsilicate taken from the group consisting of sodium silicate, potassiumsilicate, calcium silicate, and magnesium silicate, and polysilicate.The colloidal silica is preferably a mono-dispersed distribution ofcolloidal silica, and therefore, has a very narrow range of particlesizes. The filler is preferably a metal oxide taken from the groupconsisting of silicon dioxide, aluminum oxide, titanium dioxide,magnesium oxide, calcium oxide and boron oxide. The emissivity agent(s)is preferably taken from the group consisting of silicon hexaboride,carbon tetraboride, silicon tetraboride, silicon carbide, molybdenumdisilicide, tungsten disilicide, zirconium diboride, cupric chromite,and metallic oxides such as iron oxides, magnesium oxides, manganeseoxides, copper chromium oxides, and chromium oxides, cerium oxides, andterbium oxides, and derivatives thereof. The copper chromium oxide, asused in the present design, is a mixture of cupric chromite and cupricoxide. The stabilizer may be taken from the group consisting ofbentonite, kaolin, magnesium alumina silica clay, tabular alumina andstabilized zirconium oxide. The stabilizer is preferably bentonite.Other ball clay stabilizers may be substituted herein as a stabilizer.Colloidal alumina, in addition to or instead of colloidal silica, mayalso be included in the admixture of the present design. When colloidalalumina and colloidal silica are mixed together one or the otherrequires surface modification to facilitate mixing, as is known in theart.

Coloring may be added to the protective coating layer of the presentdesign to depart coloring to the oven or oven accessories. Food safepigments may be added to the protective coating without generating toxicfumes. In general, food safe pigments are divided into the subclasses:colored (salts and oxides), blacks, white and metallic.

A preferred embodiment of the present design contains a dry admixture offrom about 10% to about 25% sodium silicate, from about 50% to about 79%silicon dioxide powder, and from about 4% to about 15% of one or moreemittance agent(s) taken from the group consisting of iron oxide, boronsilicide, boron carbide, silicon tetraboride, silicon carbide molybdenumdisilicide, tungsten disilicide, zirconium diboride. Preferredembodiments of the thermal coating may contain from about 1.0% to about5.0% bentonite powder in dry admixture. The corresponding coating insolution (wet admixture) for this embodiment contains from about 10.0%to about 35.0% sodium silicate, from about 25.0% to about 50.0% silicondioxide, from about 18.0% to about 39.0% water, and from about 1.0% toabout 8.5% one or more emittance agent(s). This wet admixture must beused immediately. In order to provide a coating solution admixture (wetadmixture), which may be stored and used later, preferred embodiments ofthe thermal coating contain from about 0.25% to about 2.50% bentonitepowder. Preferably deionized water is used. Preferred embodiments of thewet admixture have a total solids content ranging from about 45% toabout 55%.

A preferred thermal protective coating of the present design contains adry admixture from about 15.0% to about 20.0% sodium silicate, fromabout 69.0% to about 79.0% silicon dioxide powder, about 1.00% bentonitepowder, and from about 5.00% to about 15.0% of an emittance agent. Theemittance agent is taken from one or more of the following: iron oxide,boron silicide, molybdenum disilicide, tungsten disilicide, and boroncarbide.

A most preferred wet admixture contains about 20.0% sodium silicatebased on a sodium silicate solids content of about 37.45%, from about34.5% to about 39.5% silicon dioxide powder, about 0.500% bentonitepowder, and from about 2.50% to about 7.5% of an emittance agent, withthe balance being water. The emittance agent is most preferably takenfrom the group consisting of iron oxide, boron silicide, and boroncarbide (also known as, carbon tetraboride). Preferred embodimentsinclude those where the emittance agent comprises about 2.50% ironoxide, about 2.50% to about 7.5% boron silicide, or from about 2.50% toabout 7.50% boron carbide. The pH of a most preferred wet admixtureaccording to the present design is about 11.2±1.0, the specific gravityis about 1.45±0.05 and the total solids content is about 50±0.3%.

A preferred embodiment of the present design contains a dry admixture offrom about 10.0% to about 30.0% colloidal silica, from about 50% toabout 79% silicon dioxide powder, and from about 2% to about 15% of oneor more emittance agent(s) taken from the group consisting of ceriumoxide, boron silicide, boron carbide, silicon tetraboride, siliconcarbide molybdenum disilicide, tungsten disilicide, zirconium diboride,and from about 1.5% to about 5.0% bentonite powder. The correspondingcoating in solution (wet admixture) for this embodiment contains fromabout 20.0% to about 35.0% colloidal silica, from about 25.0% to about55.0% silicon dioxide, from about 18.0% to about 35.0% water, and fromabout 2.0% to about 7.5% one or more emittance agent(s), and from about0.50% to about 2.50% bentonite powder. Preferably deionized water isused. Preferred embodiments of the wet admixture have a total solidscontent ranging from about 50% to about 65%.

A most preferred thermal protective coating of the present designcontains a dry admixture from about 15.0% to about 25.0% colloidalsilica, from about 68.0% to about 78.0% silicon dioxide powder, about2.00% to about 4.00% bentonite powder, and from about 4.00% to about6.00% of an emittance agent. The emittance agent is taken from one ormore of the following: zirconium boride, boron silicide, and boroncarbide.

A most preferred wet admixture contains about 27.0% colloidal silicabased on a colloidal silica solids content of about 40%, from about 25%to about 50% silicon dioxide powder, about 1.50% bentonite powder, andfrom about 2.50% to about 5.50% of an emittance agent, with the balancebeing water. The emittance agent is most preferably taken from the groupconsisting of zirconium boride, boron silicide, molybdenum disilicide,tungsten disilicide, and boron carbide. Preferred embodiments includethose where the emittance agent comprises about 2.50% zirconiumdiboride, about 2.50% boron silicide, or from about 2.50% to about 7.50%boron carbide. The specific gravity of a most preferred wet admixture isabout 1.40 to 1.50 and the total solids content is about 50% to 60%.

An inorganic adhesive, which may be used in the present design, includesN (trademark) type sodium silicate that is available from the PQCorporation (of Valley Forge, Pa.). Sodium silicates (Na₂O·XSiO₂) aremetal oxides of silica. All soluble silicates can be differentiated bytheir ratio, defined as the weight proportion of silica to alkali(SiO₂/Na₂O). Ratio determines the physical and chemical properties ofthe coating. The glassy nature of silicates imparts strong and rigidphysical properties to dried films or coatings. Silicates air dry to aspecific moisture level, according to ambient temperature and relativehumidity. Heating is necessary to take these films to complete dryness—acondition in which silicates become nearly insoluble. Reaction withother materials, such as aluminum or calcium compounds, will make thefilm coating completely insoluble. The N (trademark) type sodiumsilicate, as used in the examples below, has a weight ratioSiO.sub.2/Na.sub.2O is 3.22, 8.9% Na.sub.2O, 28.7% SiO.sub.2, with adensity (at room temperature of 20° C.) of 41.0° Be′, 11.6 lb/gal or1.38 g/cm.sup.3. The pH is 11.3 with a viscosity of 180 centipoises. TheN type sodium silicate is in a state of a syrupy liquid.

The term “total solids” refers to the sum of the silica and the alkali.The weight ratio is a most important silicate variable. Ratio determinesthe product solubility, reactivity and physical properties. Ratio iseither the weight or molar proportion of silica to alkali. Density is anexpression of total solids and is typically determined using ahydrometer or pycnometer.

Ludox (trademark) TM 50 colloidal silica and Ludox (trademark) AS 40colloidal silica are available from Grace Davidson (of Columbia, Md.).The particles in Ludox (trademark) colloidal silica are discrete uniformspheres of silica which have no internal surface area or detectablecrystallinity. Most are dispersed in an alkaline medium which reactswith the silica surface to produce a negative charge. Because of thenegative charge, the particles repel one another resulting in stableproducts. Although most grades are stable between pH 8.5-11.0, somegrades are stable in the neutral pH range. Ludox (trademark) colloidalsilicas are aqueous colloidal dispersions of very small silicaparticles. They are opalescent to milky white liquids. Because of theircolloidal nature, particles of Ludox (trademark) colloidal silica have alarge specific surface area which accounts for the novel properties andwide variety of uses. Ludox (trademark) colloidal silica is available intwo primary families: mono-dispersed, very narrow particle sizedistribution of Ludox (trademark) colloidal silica and poly-dispersed,broad particle size distribution of Ludox (trademark) P. The Ludox(trademark) colloidal silica is converted to a dry solid, usually bygelation. The colloidal silica can be gelled by (1) removing water, (2)changing pH, or (3) adding a salt or water-miscible organic solvent.During drying, the hydroxyl groups on the surface of the particlescondense by splitting out water to form siloxane bonds (Si—O—Si)resulting in coalescence and interbonding. Dried particles of Ludox(trademark) colloidal silica are chemically inert and heat resistant.The particles develop strong adhesive and cohesive bonds and areeffective binders for all types of granular and fibrous materials,especially when use at elevated temperature is required.

Colloidal alumina is available as Nyacol (trademark) colloidal alumina,and specifically, Nyacol (trademark) AL20, available from Nyacol NanoTechnologies, Inc. (Ashland, Mass.), and is available in deionized waterto reduce the sodium and chlorine levels to less than 10 ppm. Itcontains about 20 percent by weight of AL₂O₃, a particle size of 50 nm,positive particle charge, pH 4.0, specific gravity of 1.19, and aviscosity of 10 cPs.

The filler may be a silicon dioxide powder such as Min-U-Sil (trademark)5 silicon dioxide available from U.S. Silica (of Berkeley Springs, W.Va.). This silicon dioxide is fine ground silica. Chemical analysis ofthe Min-U-Sil (trademark) silicon dioxide indicates contents of 98.5%silicon dioxide, 0.060% iron oxide, 1.1% aluminum oxide, 0.02% titaniumdioxide, 0.04% calcium oxide, 0.03% magnesium oxide, 0.03% sodiumdioxide, 0.03% potassium oxide and a 0.4% loss on ignition. The typicalphysical properties are a compacted bulk density of 41 lbs/ft.sup.3, anuncompacted bulk density of 36 lbs/ft³, a hardness of 7 Mohs, hegman of7.5, median diameter of 1.7 microns, an oil absorption (D-1483) of 44, apH of 6.2, 97%-5 microns, 0.005%+325 Mesh, a reflectance of 92%, a 4.2yellowness index and a specific gravity of 2.65.

Emittance agents are available from several sources. Emissivity is therelative power of a surface to absorb and emit radiation, and the ratioof the radiant energy emitted by a surface to the radiant energy emittedby a blackbody at the same temperature. Emittance is the energyreradiated by the surface of a body per unit area.

The boron carbide, also known as carbon tetraboride, which may be usedas an emissivity agent in the present design, is sold as 1000 W boroncarbide and is available from Electro Abrasives (of Buffalo, N.Y.).Boron Carbide is one of the hardest man made materials available. Above1300° C., it is even harder than diamond and cubic boron nitride. It hasa four point flexural strength of 50,000 to 70,000 psi and a compressivestrength of 414,000 psi, depending on density. Boron Carbide also has alow thermal conductivity (29 to 67 W/mK) and has electrical resistivityranging from 0.1 to 10 ohm-cm. Typical chemical analysis indicates 77.5%boron, 21.5% carbon, iron 0.2% and total Boron plus Carbon is 98%. Thehardness is 2800 Knoop and 9.6 Mohs, the melting point is 4262° F.(2350° C.), the oxidation temperature is 932° F. (500° C.), and thespecific gravity is 2.52 g/cc.

1000 W green silicon carbide (SiC), an optional emissivity agent, isalso available from Electro Abrasives. Green Silicon Carbide is anextremely hard (Knoop 2600 or Mohs 9.4) man made mineral that possesseshigh thermal conductivity (100 W/m-K). It also has high strength atelevated temperatures (at 1100° C., Green SiC is 7.5 times stronger thanAl₂O₃). Green SiC has a Modulus of Elasticity of 410 GPa, with nodecrease in strength up to 1600° C., and it does not melt at normalpressures but instead dissociates at 2815.5° C. Green silicon carbide isa batch composition made from silica sand and coke, and is extremelypure. The physical properties are as follows for green silicon carbide:the hardness is 2600 Knoop and 9.4 Mohs, the melting point is 4712° F.(2600° C.), and the specific gravity is 3.2 g/cc. The typical chemicalanalysis is 99.5% SiC, 0.2% SiO₂, 0.03% total Si, 0.04% total Fe, and0.1% total C. Commercial silicon carbide and molybdenum disilicide mayneed to be cleaned, as is well known in the art, to eliminate flammablegas generated during production.

Boron silicide (B₆Si) is available from Cerac (of Milwaukee, Wis.). Theboron silicide, also known as silicon hexaboride, available from Cerachas a −200 mesh, and a typical purity of about 98%. Zirconium boride(ZrB₂) is also available from Cerac with a typical average of 10 micronsor less (−325 mesh), and a typical purity of about 99.5%.

Iron oxide available from Hoover Color (of Hiwassee, Va.) is a syntheticblack iron oxide (Fe₂O₃) which has an iron oxide content of 60%, aspecific gravity of 4.8 gm/cc, a tap density (also known as, bulkdensity) of 1.3 gm/cc, oil absorption of 15 lbs/100 lbs, a 325 meshresidue of 0.005, and a pH ranging from 7 to 10.

Preferably the admixture of the present design includes bentonitepowder, tabular alumina, or magnesium alumina silica clay. The bentonitepowder permits the present design to be prepared and used at a laterdate. Preparations of the present design without bentonite powder mustbe used immediately. The examples provided for the present designinclude PolarGel bentonite powder are available from Mineral and PigmentSolutions, Inc. (of South Plainfield, N.J.). Technical grade bentoniteis generally used for the purpose of suspending, emulsifying and bindingagents, and as Theological modifiers. The typical chemical analysis59.00% to 61.00% of silicon dioxide (SiO₂), 20.00% to 22.00% of aluminumoxide (Al₂O₃), 2.00% to 3.00% calcium oxide (CaO), 3.50% to 4.30%magnesium oxide (MgO), 0.60% to 0.70% ferric oxide (Fe₂O₃), 3.50% to4.00% sodium oxide (Na₂O), 0.02% to 0.03% potassium oxide (K₂O), and0.10% to 0.20% titanium dioxide and a maximum of 8.0% moisture. The pHvalue ranges from 9.5 to 10.5. Typical physical properties are 83.0 to87.0 dry brightness, 2.50 to 2.60 specific gravity, 20.82 pounds/solidgallon, 0.0480 gallons for one pound bulk, 24 ml minimum swelling power,maximum 2 ml gel formation, and 100.00% thru 200 mesh. Tabular alumina(Alumina Tab T64 Item 635) and magnesium alumina silica clay (Mag AlumSil Technical Item 105) are also available from Mineral and PigmentSolutions, Inc.

Colorants, which may be added to the present design, include but are notlimited to inorganic pigments. Suitable inorganic pigments, such asyellow iron oxide, chromium oxide green, red iron oxide, black ironoxide, titanium dioxide, are available from Hoover Color Corporation.Additional suitable inorganic pigments, such as copper chromite blackspinel, chromium green-black hematite, nickel antimony titanium yellowrutile, manganese antimony titanium buff rutile, and cobalt chromiteblue-green spinel, are available from The Shepherd Color Company (ofCincinnati, Ohio).

A surfactant and/or a dispersant may be added to the wet admixture priorto applying the thermal protective layer to the support layer. Thesurfactant was Surfyonol (trademark) 465 surfactant available from AirProducts and Chemicals, Inc. (of Allentown, Pa.). The Surfyonol(trademark) has a chemical structure of ethoxylated 2,4,7,9-tetramethyl5 decyn-4,7-diol. Other surfactants may be used, such as STANDAPOL(trademark) T, INCI which has a chemical structure of triethanolaminelauryl sulfate, liquid mild primary surfactant available fromCognis-Care Chemicals (of Cincinnati, Ohio). The amount of surfactantpresent by weight in the wet admixture in from about 0.05% to about0.2%.

The thermal protective coating is applied to the surface to form athermal protective layer. The substrate surface may be a metallicsubstrate such as iron, aluminum, alloys, steel, cast iron, stainlesssteel and the like, or it may be a ceramic surface, as is well known inthe art. The coating is typically applied wet, and either allowed to airdry or heat dry.

Substrate surface preparations for metal, alloy, or ceramic surfaces areslightly different. The present design may be used with new ovens whichwill need limited surface preparation, or may be used to refit oldovens. In either case, the substrate surface should be clear of alldirt, loose material, surfactants, oils, any foreign matter, etc. Ametal surface in a new or used oven may be grit blasted, if necessary.Grit blasting may be desirable to remove oxidation, other contaminants,and to improve the profile for metal surfaces only. Grits media shouldbe sharp particles. Gun pressure will vary depending on the cut type,condition of the metal and profile desired. Old metal will requirehigher psi, such as up to 70-80 psi. Oil and water-free compressed airis required. Proper filters for the removal of oil and water arerequired. Other alkaline type metal cleansers may also be utilized.Ceramic surfaces that has been cleaned and cured is cleaned by lightwire brushing and vacuuming of the surface.

After the grit blast, the surface should be thoroughly cleaned to removeall loose particles with clean oil and water free air blasts. Avoidcontaminating surface with fingerprints. Acetone can be used (underproper ventilation and exercising all necessary precautions when workingwith acetone) on a clean cloth to wipe metallic surfaces clean. Acleaning compound may be used on certain stainless steel in lieu of gritblasting. Many alkaline metal cleaners (powdered or liquid) are known inthe art and may be used provided, however, that the surface isthoroughly cleaned with no residue or particulates remaining. Ceramicsurfaces do not need further cleaning, but might be cleaned usingacetone where oil or the like has spilled on the surface.

When using wet admixture, solids may settle during shipment or storage.Prior to use all previously mixed coating must be thoroughly re-mixed toensure all settled solids and clumps are completely re-dispersed. Whennot using a stabilizer, the coating may not be stored for any period oftime. In any case, the coating should be used immediately after mixingto minimize settling.

Mixing instructions for one and five gallon containers. High speed/highshear saw tooth dispersion blade 5″ diameter for one gallon containersand 7″ diameter for five gallon containers may be attached to a handdrill of sufficient power with a minimum no load speed of 2000 rpmshear. Dispersion blades can be purchased from numerous suppliers. Mixat high speed to ensure complete re-dispersion for a minimum of 30minutes.

The product should be applied directly after cleaning a metal surface sominimal surface oxidation occurs. The product should be applied in aproperly ventilated and well lit area, or protective equipment should beused appropriate to the environment, for example within a firebox. Themixed product should not be filtered or diluted.

A high volume low pressure (HVLP) spray gun should be used with 20-40psi of clean, oil and water free air. Proper filters for removal of oiland water are required. Alternatively, an airless spray gun may be used.Other types of spray equipment may be suitable. The applicator shouldpractice spraying on scrap metal prior to spraying the actual part toensure proper coverage density. An airless spray system is preferablefor applications on ceramic surfaces such as the refractory materials. Ahigh speed pot agitator system may be desirable for metal applications.Suitable spray gun tips may be selected to provide the proper thicknesswithout undue experimentation.

Controlling the coverage density may be critical to coating performance.The thermal layer thickness should be from about one (1) mils (about 25microns (μ)) to about four (4) mils (about 100μ), depending upon typed,size and condition of substrate. One (1) mil equals 25.4μ. Properthickness may vary. If possible, rotate the part 90 degrees at leastonce to maintain even coverage. Allow 1 to 4 hours of dry time beforethe part is handled, depending upon humidity and temperature.

Example 1 contains N grade Sodium Silicate 15.0% dry weight and 20.0%wet weight based on sodium silicate solids content of 37.45%, Min-U-Sil5 SiO₂ powder 79.0% dry weight and 39.5% wet weight, 1000 W B₄C 5.00%dry weight and 2.50% wet weight, PolarGel bentonite powder (Item#354)1.00% dry weight and 0.500% wet weight, and 37.5% water, based on sodiumsilicate solids content of 37.45%. The pH of example 1 is 11.2±1.0, thespecific gravity is 1.45±0.05, and the total solids content is 50±0.3%.Example 1 is prepared by placing the liquid ingredients in a clean,relatively dry mixing container. While mixing, the remaining ingredientsare added slowly to the mixture to prevent the powders from clumping andsticking to the side of the mixing container. The mixture is then mixedat high power for at least 20 minutes depending on the configuration ofthe mixer. The mixing was carried out in a high shear mixer with a 2.5inch Cowles Hi-Shear Impeller blade with a 0.5 horsepower motorgenerating 7500 rpm without load.

Example 2 contains N grade Sodium Silicate 15.0% dry weight and 20.0%wet weight based on sodium silicate solids content of 37.45%, min-U-Sil5 SiO₂ powder 69.0% dry weight and 34.5% wet weight, 1000 W B₄C 15.0%dry weight and 7.5% wet weight, PolarGel bentonite powder (Item#354)1.00% dry weight and 0.500% wet weight, and 37.5% water, based on sodiumsilicate solids content of 37.45%. The pH of example 2 is 11.2±1.0, thespecific gravity is 1.45±0.05, and the total solids content is 50±0.3%.Example 2 is prepared in the same fashion as example 1.

Example 3 contains N grade Sodium Silicate 15.0% dry weight and 20.0%wet weight based on sodium silicate solids content of 37.45%, min-U-Sil5 SiO.sub.2 powder 79.0% dry weight and 39.5% wet weight, boron silicide5.00% dry weight and 2.50% wet weight, PolarGel bentonite powder(Item#354) 1.00% dry weight and 0.500% wet weight, and 37.5% water,based on sodium silicate solids content of 37.45%. The pH of example 3is 11.2±1.0, the specific gravity is 1.45±0.05, and the total solidscontent is 50±0.3%. Example 3 is prepared in the same fashion as example1.

Example 4 contains N grade Sodium Silicate 15.0% dry weight and 20.0%wet weight based on sodium silicate solids content of 37.45%, min-U-Sil5 SiO₂ powder 79.0% dry weight and 39.5% wet weight, iron oxide 5.00%dry weight and 2.50% wet weight, PolarGel bentonite powder (Item#354)1.00% dry weight and 0.500% wet weight, and 37.5% water, based on sodiumsilicate solids content of 37.45%. The pH of example 4 is 11.2±1.0, thespecific gravity is 1.45±0.05, and the total solids content is 50±0.3%.Example 4 is prepared in the same fashion as example 1.

An example of the present design involved adding high emissivity coatedpanels to the entire inside of a direct fired traveling tray (tunnel)oven. The resultant oven reduced the baking time and increasedproduction by 5%. Anticipated reduction of baking time and increase ofproduction up to 20% is expected. Energy efficiency of over 20% wasachieved. Additionally having emissivity panels disposed throughout theentire inside of the oven resulted to more consistent product height.Excess air was reduced by 2.7 times. The combustion efficiency of thedirect fired traveling tray oven was increased by 27%. Improvements tobaking overall are expected to be a reduction of baking time by up to50% resulting in the increased productivity of the oven, and reductionof the amount of energy up to 50% needed to bake a unit mass of product.

It is to be understood that the present design is not limited to theembodiments described above, but encompasses any and all embodimentswithin the scope of the following claims.

What is claimed is:
 1. A process of making a food product, comprising:providing an oven having a housing including a ceiling, a floor, twoopposite side walls, and an opening therethrough forming at least oneinternal heating zone for receiving an oven cooking accessory therein;heating means comprising burners, burners shielded by burner shields, orelements for providing heat to the heating zone; and a high emissivitythermal protective layer disposed on at least one substrate surfacetherein in which the substrate surface comprises a metal or ceramicsurface disposed within the oven housing, and is taken from the groupconsisting of the floor, ceiling, or side walls of the housing, theburners, burner shields, or elements of the heating means, an accessorydisposed within the housing, or combinations thereof; wherein the highemissivity thermal protective layer comprises from about 5% to about 30%of an inorganic adhesive, from about 45% to about 92% of at least onefiller, and from about 1% to about 25% of one or more emissivity agents;or from about 5% to about 35% of colloidal silica, colloidal alumina, orcombinations thereof, from about 23% to about 79% of at least onefiller, and from about 1% to about 25% of one or more emissivity agents;providing a cooking accessory for holding a mixed recipe or prepareddough during heating; holding the mixed recipe or prepared dough in thecooking accessory; and heating the cooking accessory in at least oneheating zone until the food product is ready; thereby making a uniformlycooked food product.
 2. The process of making a food product accordingto claim 1, wherein: the thermal protective layer further comprises fromabout 1.0% to about 5.0% of a stabilizer; the thermal protective layerfurther comprises a surfactant or dispersant; the thermal protectivelayer further comprises a colorant; the inorganic adhesive is taken fromthe group consisting of an alkali/alkaline earth metal silicate takenfrom the group consisting of sodium silicate, potassium silicate,calcium silicate, and magnesium silicate; the filler is taken from thegroup consisting of silicon dioxide, aluminum oxide, titanium dioxide,magnesium oxide, calcium oxide, and boron oxide; the one or moreemissivity agents are taken from the group consisting of siliconhexaboride, boron carbide, silicon tetraboride, silicon carbide,molybdenum disilicide, tungsten disilicide, zirconium diboride, cupricchromite, and metallic oxides; or combinations thereof; the stabilizeris taken from the group consisting of bentonite, kaolin, magnesiumalumina silica clay, tabular alumina, and stabilized zirconium oxide;the thermal protective layer is from about one (1) mils (about 25microns (μ) to about four (4) mils (about 100 μ) thick; or combinationsthereof.
 3. The process according to claim 1, wherein: a thermalprotective layer contains from about 5% to about 30% of an inorganicadhesive, the inorganic adhesive is taken from the group consisting ofan alkali/alkaline earth metal silicate taken from the group consistingof sodium silicate, potassium silicate, calcium silicate, magnesiumsilicate, and polysilicate; from about 45% to about 92% of at least onefiller, the filler taken from the group consisting of silicon dioxide,aluminum oxide, titanium dioxide, magnesium oxide, calcium oxide, andboron oxide; and from about 1% to about 25% of one or more emissivityagents taken from the group consisting of silicon hexaboride, boroncarbide, silicon tetraboride, silicon carbide, molybdenum disilicide,tungsten disilicide, zirconium diboride, cupric chromite, and metallicoxides; from about 5% to about 35% of colloidal silica, colloidalalumina, or combinations thereof; from about 23% to about 79% of atleast one filler taken from the group consisting of silicon dioxide,aluminum oxide, titanium dioxide, magnesium oxide, calcium oxide, andboron oxide; and from about 1% to about 25% of one or more emissivityagents taken from the group consisting of silicon hexaboride, boroncarbide, silicon tetraboride, silicon carbide, molybdenum disilicide,tungsten disilicide, zirconium diboride, cupric chromite, and metallicoxides; from about 5% to about 30% of an inorganic adhesive, theinorganic adhesive is taken from the group consisting of analkali/alkaline earth metal silicate taken from the group consisting ofsodium silicate, potassium silicate, calcium silicate, magnesiumsilicate, and polysilicate; from about 45% to about 92% of at least onefiller, the filler taken from the group consisting of silicon dioxide,aluminum oxide, titanium dioxide, magnesium oxide, calcium oxide, andboron oxide; and from about 1% to about 25% of one or more emissivityagents taken from the group consisting of silicon hexaboride, boroncarbide, silicon tetraboride, silicon carbide, molybdenum disilicide,tungsten disilicide, zirconium diboride, cupric chromite, and metallicoxides; and from about 1% to about 5% of a stabilizer taken from thegroup consisting of bentonite, kaolin, magnesium alumina silica clay,tabular alumina, and stabilized zirconium oxide; from about 5% to about35% of colloidal silica, colloidal alumina, or combinations thereof;from about 23% to about 79% of at least one filler taken from the groupconsisting of silicon dioxide, aluminum oxide, titanium dioxide,magnesium oxide, calcium oxide, and boron oxide; and from about 1% toabout 25% of one or more emissivity agents taken from the groupconsisting of silicon hexaboride, boron carbide, silicon tetraboride,silicon carbide, molybdenum disilicide, tungsten disilicide, zirconiumdiboride, cupric chromite, and metallic oxides; and from about 1.5% toabout 5.0% of a stabilizer taken from the group consisting of bentonite,kaolin, magnesium alumina silica clay, tabular alumina, and stabilizedzirconium oxide; from about 10% to about 30% sodium silicate, from about50% to about 79% silicon dioxide powder, and from about 4% to about 15%of one or more emissivity agents taken from the group consisting of ironoxide, boron silicide, boron carbide, silicon tetraboride, siliconcarbide powder, molybdenum disilicide, tungsten disilicide, andzirconium diboride; from about 10% to about 30% sodium silicate, fromabout 50% to about 79% silicon dioxide powder, from about 4% to about15% of one or more emissivity agents taken from the group consisting ofiron oxide, boron silicide, boron carbide, silicon tetraboride, siliconcarbide powder, molybdenum disilicide, tungsten disilicide, andzirconium diboride, and from about 1% to about 5% of a stabilizer takenfrom the group consisting of bentonite, kaolin, magnesium alumina silicaclay, tabular alumina, and stabilized zirconium oxide; from about 10% toabout 30% colloidal silica, from about 50% to about 79% silicon dioxidepowder, and from about 2% to about 15% of one or more emissivity agentstaken from the group consisting of iron oxide, boron silicide, boroncarbide, silicon tetraboride, silicon carbide molybdenum disilicide,tungsten disilicide, and zirconium diboride; or from about 10% to about30% colloidal silica, from about 50% to about 79% silicon dioxidepowder, from about 2% to about 15% of one or more emissivity agentstaken from the group consisting of iron oxide, boron silicide, boroncarbide, silicon tetraboride, silicon carbide molybdenum disilicide,tungsten disilicide, and zirconium diboride, and from about 1.5% toabout 5.0% of a stabilizer taken from the group consisting of bentonite,kaolin, magnesium alumina silica clay, tabular alumina, and stabilizedzirconium oxide.
 4. The process according to claim 1, wherein: ametallic surface forms at least a substrate surface disposed within theoven comprised of iron, aluminum, alloys, steel, cast iron, stainlesssteel, and combinations thereof.
 5. The process of making a food productaccording to claim 1, further comprising: a cooking accessory comprisinga cooking surface for coming into contact with food; an outside surfaceopposite the cooking surface; and the high emissivity thermal protectivelayer disposed on a surface of the cooking accessory.
 6. The process ofmaking a food product according to claim 1, wherein the cookingaccessory is taken from the group consisting of pans, sheets, forms,racks, and combinations thereof.
 7. The process of making a foodproduct, according to claim 1, further comprising: moving the cookingaccessory to facilitate heating in at least two heating zones.
 8. Theprocess of making a food product, according to claim 7, wherein: thecooking accessory is provided on a belt or roller conveyor system havinga high emissivity thermal protective layer disposed at least partiallythereon.
 9. The process of making a food product, according to claim 1,wherein: the high emissivity thermal protective layer is disposed on atleast one coated panel or on a coated insert; the panel or insertdistributed within the oven covering at least one wall, floor, ceiling,or combinations thereof.
 10. The process of making a food product,according to claim 4, wherein: the thermal protective layer is disposedon a the cooking accessory is a pan or sheet.
 11. The process of makinga food product, according to claim 4, wherein: the thermal protectivelayer is disposed on a removable accessory including a panel or aninsert.
 12. The process of making a food product, according to claim 4,further comprising: the thermal protective layer is disposed on at leastone rack disposed within the housing to support the food product. 13.The process of making a food product, according to claim 4, furthercomprising: the thermal protective layer is disposed on a conveyor,belt, roller, or combination thereof disposed within the housing to movethe food product between heating zones.
 14. The process of making a foodproduct, according to claim 4, wherein: the housing further comprises adoor and backwall opposite the door having the thermal protective layerdisposed on a substrate surface of the door, backwall, or combinationsthereof.
 15. The process of making a food product according to claim 4,wherein: the thermal protective layer is disposed on a substrate surfaceof the burner shield.